Selective alkylation of aromatic hydrocarbons



llnited 3,fi86,998 Patented Apr. 23, 1963 ice 3,08\,998 SELEiITIVE ALKYLATIQN F AROMATEC HYDRQCARBGNS George L. Hervert, Downers Grove, and Carl B. Linn,

Riverside, 111., assignors to Universal Oil Products Company, Des lllaines, 111., a corporation of Delaware No Drawing. Filed Sept. 12, 1960, Ser. No. 55,141 19 Claims. (Cl. 26067 1) This invention relates to a process for the alkylation of aromatic hydrocarbons, and particularly the invention relates to a process for the alkylation of aromatic hydrocarbons with olefin-acting compounds in the presence of a novel catalytic composition of matter. Still more particularly this invention is concerned with a process for selectively alkylating aromatic hydrocarbons with olefin-acting compounds in the presence of a catalyst comprising boron trifiuoride and boron trifiuoride-modified sulfur containing alumina.

An object of this invention is to produce selective alkylated aromatic hydrocarbons and more particularly to produce selective alkylated benzene hydrocarbons.

A specific object of this invention is to provide a process for the production of cumene by the reaction of benzene with propylene, which cumene product may be oxidized to form cumene hydroperoxide, the latter compound being readily decomposed by the addition of an acidic substance to form phenol and acetone along with minor amounts of acetophenone.

In addition, another object of this invention is to produce para-diisopropylbenzene.which may be oxidized to form terephthalic acid, one starting material for the production of certain synthetic fibers. Also the process of the invention may be used to produce alkyl-arornatic hydrocarbons boiling within the gasoline boiling range having high anti-knock value and which may be used as such or as components of gasoline suitable for use in automobile engines.

Still another object of this invention is the selective alkylation of aromatic hydrocarbons with so-called refinery off-gases or mixtures of olefins and parafiins in which the desired olefins such as propylene which are to be used as alltylating agents are present in concentrations so low that such streams have not been utilized satisfactorily as alkylating agents in existing processes without prior intermediate olefin concentration steps.

These and other objects of this invention will be set forth hereinafter in detail as part of the accompanying specification.

Previously, it has been suggested that boron trifluoride can be utilized as a catalyst for the alkylation of aromatic hydrocarbons with unsaturated hydrocarbons. For example, Hofmann and Wulff succeeded in replacing aluminum chloride by boron trifluoride for catalysis of condensation reactions of the Friedel-Crafts type (German Patent 513,414, British Patent 307,802 and French Patent 665,812). Aromatic hydrocarbons such as benzene, toluene, tetralin, and naphthalene have been condensed with ethylene, propylene, isononylene, and cyclohexene in the presence of boron trifiuoride with the production of the corresponding monoand polyalkylated aromatic hydrocarbon derivatives. In these processes rather massive amounts of boron trifluoride have been utilized as the catalyst. Similarly, the olefin utilized has been pure or substantially pure. No successful processes have yet been introduced in which the olefin content of a gas stream, which is rather dilute in olefins, has been successfully consumed to completion in the absence of some olefin concentration step or steps. By the use of the process of the present invention, such gas streams may be utilized per se as alkylating agents and substantially complete conversions of propylene to make cumene are obtained, while ethylene is recovered as the only remaining olefin.

One embodiment of this invention resides in a process for the production of a selective alkylaromatic hydrocarbon which comprises passing an alkylatable aromatic hydrocarbon, olefin-acting compounds and not more than 0.8 gram of boron trifiuoride per gram mol of olefin-acting compounds to an alkylation zone containing a boron trifluoride modified, sulfur containing alumina, reacting therein said alkylatable aromatic hydrocarbon with said olefin-acting compounds at alkylation conditions in the presence of an alkylation catalyst comprising said boron trifluoride modified, sulfur containing alumina, and recovering therefrom selectively alkylated aromatic hydrocarbon and unreacted olefin compound.

A further embodiment of this invention is found in a process for the production of a selective alkylaromatic hydrocarbon which comprises passing an alkylatable aromatic hydrocarbon, unsaturated hydrocarbons and up to about 0.8 gram of boron trifluoride per gram mol of unsaturated hydrocarbons to an alkylation zone containing a boron trifiuoride modified, sulfur containing gamma-alumina, and reacting therein said alkylatable aromatic hydrocarbon with said unsaturated hydrocarbons at alkylation conditions in the presence of an alkylation catalyst comprising boron trifluoride modified, substantially anhydrous sulfur containing gamma-alumina, and recovering therefrom selectively alkylated aromatic hydrocarbon and unreacted unsaturated hydrocarbon.

Yet another embodiment of the invention resides in a process for the production of cumene which comprises passing benzene, an ethylene-propylene mixture and from about 0.001 gram to about 0.8 gram of boron trifiuoride per gram mol of propylene to an alkylation zone containing boron trifluoride modified, substantially anhydrous sulfur containing gamma-alumina. reacting therein said benzene with said ethylene-propylene mixture at alkylation conditions in the presence of an alkylation catalyst comprising said boron trifluoride and boron trifluoride modified, sulfur containing gamma-alumina, and recovering therefrom cumene and unreacted ethylene.

A specific embodiment of the invention resides in a process for the production of cumene which comprises passing benzene, an ethylene-propylene mixture and from about 0.001 gram to about 0.8 gram \of boron trifiuoride per gram mol of propylene to an alkylation zone containing boron trifluoride modified, substantially anhydrous gamma-alumina containing from about 0.1 to about 10% by weight of sulfur based on the alumina, reacting therein said benzene with said ethylene-propylene mixture at a temperature in the range of from about 0 to about 300 C. and at a pressure in the range of from about atmospheric to about 200 atmospheres in the presence of an alkylation catalyst comprising said boron trifiuoride and boron triiluoride modified, sulfur containing gammaalumina, and recovering therefrom cumene and unreacted ethylene. Other objects and embodiments referring to alternative .alkylatable aromatic hydrocarbons, olefin-acting compounds and alkylation catalysts will be found in the following further detailed description of the invention.

It has now been found that, when utilizing a catalyst comprising boron trifluoride and a boron trifluoride modified, substantially anhydrous sulfur containing inorganic oxide, a selective alkylation of aromatic hydrocarbons with olefins is obtained. Therefore, the process of this invention may be utilized to separate an olefin mixture containing ethylene together with other olefins such as propylene, butylenes, etc., by subjecting an alkylatable aromatic hydrocarbon to the action of said olefinic mixture in the presence of a catalyst hereinafter described, the higher molecular weight olefins thereby reacting with the aromatic hydrocarbon to the exclusion of the ethylene. The unreacted ethylene may then be separated and recovered from the reaction mixture and further utilized in processes where other olefins are not desirable.

The substantially anhydrous inorganic oxide such as gamma-, eta-, or theta-alumina is first treated With a sulfur containing compound by contacting said alumina with a sulfur containing compound in an amount of from about 0.01% to about 25% by weight of the sulfur compound based on the alumina at a temperature ranging from about room temperature (25 C.) up to about 300 C. The alumina may, in one manner of operation, be placed as a fixed bed in a reaction zone and the desired quantity of the sulfur compound in either gaseous or liquid form passed therethrough, or if so desired the alumina may be admixed with a sulfur compound dissolved in a substantially inert organic solvent and the sulfur compound allowed to remain in contact with the alumina for a predetermined period of time ranging from about 4 to about 72 hours or more. The sulfur containing compound, examples of which include hydrogen sulfide, thiophene, othioxene, m-thioxene, thiophenol, methyl mercaptan, ethyl mercaptan, n-propyl mercaptan, isopropyl mercaptan, the butyl mercaptans, the amyl mercaptans, the hexyl mercaptans, the heptyl mercaptans, -etc., may be utilized in the required amount per se or may be used in dilute form by being diluted With various other gases.

Boron trifluoride is a gas (Bl ll C., M.P. -l26 C.) which is appreciably soluble in many organic solvents. It may be utilized per se by merely bubbling into a reaction mixture or it may be utilized as a solution of the gas in an organic solvent such as the aromatic hydrocarbon to be alkylated, for example, benzene. Such solutions are within the generally broad scope of the use of a boron trifluoride modified catalyst in the presence of the present invention although not necessarily with equivalent results. Gaseous boron trifluoride is preferred.

The preferred catalyst composition, as stated hereinabove, comprises boron trifluoride and boron trifluoride modified substantially anhydrous but not completely dry alumina containing sulfur. Of the various types of alumina containing sulfur which may be successfully and satisfactorily modified with boron trifluoride, three crystalline structures of alumina have been found to be particularly suitable. These crystalline structures are substantially anhydrous gamma-alumina, substantially anhydrous eta-alumina and substantially anhydrous theta-alumina. The exact reason for the specific utility of these three crystalline alumina modifications in the process of this invention is not fully understood but it is believed to be connected with the number of residual hydroxyl groups on the surface of these three particular crystalline alumina modifications. It has been established, for example, that other crystalline alumina modifications such as gamma-alumina trihydrate (Al O 3H O) or anhydrous alpha-alumina are less active and cannot be utilized in the process of this invention in the same manner as substantially anhydrous gamma-alumina, substantially anhydrous eta-alumina and substantially anhydnous theta-alumina are used whenever complete olefin consumption is required. Modification of sulfur containing aluminas with boron trifluoride may be carried out prior to the addition of the alumina to the alkylation reaction zone or this modification may be carried out in situ. Furthermore, this modification of the alumina with boron trifluoride may be carried out prior to contact of these boron trifluoride modified aluminas with the aromatic hydrocarbon to be alkylated and the olefin-acting compound, or the modification may be carried out in the presence of the aromatic hydrocarbon to be alkylated, or in the presence of both the aromatic hydrocarbon to be alkylated and the olefin-acting compound. Obviously there is some limitation upon this last mentioned method of alumina modification. The modification of the above mentioned aluminas with boron trifluoride is an exothermic reaction and care must be taken to provide for proper removal of the resultant heat. The modification of the alumina is carried out by contacting the alumina With from about 2% to about 50% by Weight boron trifluoride based on the alumina. In one manner of operation, the sulfur containing alumina is placed as a fixed bed in a reaction zone, which may be the alkylation reaction zone, and the desired quantity of boron trifluoride is passed therethrough. In such a case, the boron trifluoride may be utilized in so-called massive amounts or may be used in dilute form diluted with various other gases such as hydrogen, nitrogen, helium, etc. This contacting is normally carried out at room temperature (25 C.) although temperatures up to that to be utilized for the alkylation reaction, that is, temperatures up to about 300 C. may be used. With the preselected sulfur containing alumina at room temperature, utilizing boron trifluoride alone, a temperature wave will travel through the alumina bed during this modification of the alumina with boron trifluoride, increasing the temperature of the alumina from room temperature up to about C. or more. As the boron trifluoride content of the gases to be passed over the alumina is diminished, this temperature increase also diminishes and can be controlled more readily in such instances. In another method for the modification of the above mentioned sulfur containing gamma-, etaand theta-aluminas with boron trifluoride, said alumina may be placed as a fixed bed in the alkylation reaction zone, the boron trifluoride dissolved in the aromatic hydrocarbon to be alkylated, and the solution of aromatic hydrocarbon and boron trifluoride passes over the alumina at the desired temperature until sufficient boron trifluoride has modified the alumina. When the gas phase treatment of the alumina is carried out, it is noted that no boron trifluoride passes through the alumina bed until all of the alumina has been modified by the boron trifluoride. This same phenomena is observed during the modification of the alumina with the aromatic hydrocarbon solutions containing boron trifluoride. In another method, the modification of the alumina can be accomplished by utilization of a mixture of aromatic hydrocarbon to be alkylated, olefin-acting compound, and boron trifluoride which upon passage over the alumina forms the desired boron trifluoride modified sulfur containing alumina in situ. In the latter case, of course, the activity of the system is low initially and increases as the complete modification of the alumina with the boron trifluoride takes place. The exact manner by which the boron trifluoride modifies the sulfur containing alumina is not understood. It may be that the modification is a result of complexing of the boron trifluoride with the alumina, or on the other hand, it may be that the boron trifluoride reacts with residual hydroxyl groups on the alumina surface. It has been found at any particular preselected temperature for treatment of substantially anhydrous alumina, utilizing either the gamma-, etaor theta-alumina modifications as set forth hereinabove, that the fluorine content of the treated aluminas attains a maximum which is not increased by further passage of boron trifluoride over the same. This maximum fluorine or boron trifluoride content of the alumina increases with temperature and depends upon the specific alumina selected. As stated hereinabove, the alumina treatment is, in the preferred embodiment, carried out at a temperature equal to or just greater than the selected reaction temperature so that the alumina Will not necessarily tend to be modified further by the boron trifluoride which may be added in amounts not more than 0.8 gram per gram mol of olefin-acting compound during the process and so that control of the aromatic hydrocarbon alkylation reaction is attained more readily. In any case, the alumina resulting from any of the above mentioned boron trifluoride treatments is referred to herein in the specification and claims as boron trifluoride modified substantially anhydrous alumina.

It is also contemplated within the scope of this invention that the alumina, either -gamma-, eta-, or thetain character, may be modified with boron trifluoride in one of the methods hereinbefore set forth, and the resultant boron trifluoride modified substantially anhydrous alumina is then treated with a sulfur containing compound of the type hereinabove mentioned in any manner known in the art to produce the desired catalyst.

As set forth hereinabove, the present invention relates to a process for the alkylation of an alkylatable aromatic hydrocarbon with a mixture of olefin-acting compounds in the presence of a catalyst comprising a boron trifluoride modified substantially anhydrous sulfur containing inorganic oxide, and particularly in the presence of a catalyst comprising not more than 0.8 gram of boron trifluoride per gram mol of olefin-acting compounds and a boron trifiuoride modified substantially anhydrous sulfor containing alumina. Many aromatic hydrocarbons are utilizable as starting materials in the process of this invention. Preferred aromatic hydrocarbons are monocyclic aromatic hydrocarbons, that is, benzene hydrocarbons. Suitable aromatic hydrocarbons include benzene, toluene, ortho-xylene, meta-xylene, para-xylene, ethylbenzene, or-tho-ethyltoluene, meta-ethyltoluene, para-ethyltoluene, 1,2,3-trimethylbenzene, 1,2,4-trimethylbenzene, 1,3,5-trimethylbenzene or mesitylene, normal propylbenzene, isopropylbeuzene, etc. Higher molecular weight alkylaromatic hydrocarbons are also suitable as starting materials and include aromatic hydrocarbons such as are produced by the alkylation of aromatic hydrocarbons with olefin polymers. Such products are frequently referred to in the art as alkylate, and include hexylbenzene, nonylbenzene, dodecyltoluene, pentadecyltoluene, etc. Very often 'alkylate is obtained as a high boiling fraction in which the alkyl group attached to the aromatic nucleus varies in size from about C to about C Other suitable alkylatable aromatic hydrocarbons include those with two or more aryl groups such as diphenyl, diphenylmethane, triphenyl, tri-phenylmethane, fiuorene, stilbene, etc. Examples of other alky-la-table aromatic hydrocarbons within the scope of this invention as starting materials contain ing condensed benzene rings include naphthalene, alphamethylnaphthalene, beta-methylnaphthalene, anthracene, phenanthrene, naphthacene, rubrene, etc. Of the above alkylatable aromatic hydrocarbons for use as starting materials in the process of this invention, the benzene hydrocarbons are preferred, and of the preferred benzene hydrocarbons, benzene itself is particularly preferred.

Suitable olefin-acting componds or alkylating agents which may be charged in the process of this invention include monoolefins, diolefins, polyolefins, acetylenic hydrocarbons, and also alkyl chlorides, alkyl bromides, and alkyl iodides. The preferred olefin-acting compounds are olefinic hydrocarbons which comprise monoolefins having one double bond per molecule and polyolefins which have more than one double bond per molecule. Monoolefins which may be utilized as olefin-acting compounds or alkylating agents for alkylating alkylatable aromatic hydrocarbons in the presence of the hereinabove described catalyst are either normally gaseous or normal- 1y liquid and include propylene, l-butene, Z-butene, isobutylene, and higher normally liquid olefins such as pentenes, hexenes, heptenes, octenes, and higher molecular weight liquid olefins, the latter including various olefin polymers having from about -6 to about 18 carbon atoms per molecule such as propylene trimer, propylene tetramer, propylene pentamer, isobutylene dimer, isobutylene trimer, isobutylene tetramer, etc. Cycloolefins such as cyclopentene, methylcyclopentene, cyclohexene, methylcyclohex-ene, may be utilized, but generally not under the same conditions of operation applying to non-cyclic olefins. The polyolefinic hydrocarbons utilizable in the process of this invention include conjugated diolefins such as butadiene and isoprene, aswell as non-conjugated diolefins and other polyolefinic hydrocarbons containing two or more double bonds per molecule.

As stated hereinabove, alkylation of the above alkylatable aromatic hydrocarbons may also be effected in the presence of the hereinabove referred to catalyst by reacting aromatic hydrocarbons with certain substances capable of producing olefinic hydrocarbons, or intermediates thereof, under the conditions of operation chosen for the process. Typical olefin producing substances capable of use include alkyl chlorides, alkyl bromides, and alkyl iodides capable of undergoing dehydrohalogenation to form olefinic hydrocarbons and thus containing at least two carbon atoms per molecule. Examples of such alkyl halides include n-propyl chloride, isopropyl chloride, nbutyl chloride, sec-butyl chloride, t-butyl chloride, the amyl chlorides, hexyl chlorides, etc., propyl bromide, isopropyl bromide, n-butyl bromide, sec-butyl bromide, tbutyl bromide, the amyl bromides, hexyl bromides, etc., n-propyl iodide, etc.

As stated hereinabove, olefin hydrocarbons, especially normally gaseous olefin hydrocarbons, are particularly preferred olefin-acting compounds or alkylating agents for use in the process of the present invention. As stated, the process can be successfully applied to and utilized for conversion of olefinic hydrocarbons when these olefinic hydrocarbons are present in minor quantities in gas streams. Thus, in contrast to prior art processes, the normally gaseous olefinic hydrocarbon for use in the process of the present invention, need not be purified or concentrated. Such normally gaseous olefinic hydrocarbons appear in minor concentrations in various refinery gas streams, usually diluted with various unreactive gases such as hydrogen, nitrogen, methane, ethane, propane, etc. These gas streams containing minor quantities of olefinic hydrocarbon are obtained in petroleum refineries from various refinery installations including thermal cracking units, catalytic cracking units, thermal reforming units, coking units, polymerization units, etc. Such refinery gas streams have in the past often been burned for fuel value since an economical process for their utilization as alkylating agents or olefin-acting compounds has not been available except where concentration of the olefinic hydrocarbons has been carried out concur rently therewith. These refinery gas streams containing minor quantities of olefinic hydrocarbons are known as off-gases or tail gases. In addition to containing minor quantities of olefin hydrocarbons such as ethylene, propyl ene, and the various butenes, depending upon their source, they contain varying quantities of nitrogen, hydrogen, and various normally gaseous olefinic hydrocarbons. Thus, a refinery olf-gas ethylene-propylene stream may contain varying quantities of hydrogen, nitrogen, meth ane, ethane and propane with the ethylene and propylene in minor proportions. A typical analysis in mol percent for a utilizable refinery off-gas from a catalytic cracking unit is as follows: nitrogen, 40%; carbon monoxide, 0.2%; hydrogen, 5.4%; methane, 37.8%; ethylene, 10.3%; ethane, 24.7%; propylene, 6.4%; propane, 10.7%; and C hydrocarbons, 0.5%. It is readily observed that the total olefin content of this gas stream is 116.7%. Such gas streams containing olefinic hydrocarbons in minor or dilute quantities are particularly preferred alkylating agents or olefin-acting compounds within the broad scope of the present invention. Among the olefins present insuch streams only propylene is selectively reacted with the alkylatable aromatic compound according to the process of this invention, thus effectively separating the remaining olefin comprising ethylene which is utilized in various other petrochemical processes.

In accordance with the process of the present invention, the selective alkylation of alkylatable aromatic hydrocarbons with olefin-acting compounds or mixtures thereof reacts to produce selective alkylated aromatic hydrocarbons of higher molecular weight than those charged to the process, the process being effected in the presence of the above indicated catalyst at a temperature of from about C. or lower to about 300 C. or higher, and preferably from about 20 to about 230 C., although the exact temperature needed for a particular selective aromatic hydrocarbon alkylation reaction will depend upon the alkylatable aromatic hydrocarbon and olefin-acting compound or compounds employed. The term selective alkylaromatic hydrocarbon as used in the specification and appended claims will refer to the product obtained when an aromatic hydrocarbon is alkylated with a mixture of olefins including ethylene and a higher molecular weight olefin in the presence of the catalyst of the present invention, the ethylene remaining unreacted while the aromatic hydrocarbon is alkylated by reaction with the other olefin such as propylene, butylene, etc. The selective alkylation reaction is usually carried out at a pressure of from about substantially atmospheric to about 200 atmospheres. The pressure utilized is usually selected to maintain the alkylatable aromatic hydrocarbon in substantially liquid phase. Within the above temperature and pressure ranges, it is not always possible to maintain the olefin-acting compound or compounds in liquid phase. Thus, when utilizing a refinery off-gas containing minor quantities of ethylene and propylene, the ethylene and propylene will be dissolved in the liquid phase alkylatable aromatic hydrocarbon to the extent governed by temperature, pressure, and solubility considerations. However, a portion thereof undoubtedly will be in the gas phase. When possible, it is preferred to maintain all of the reactants in liquid phase. Such is not always possible, however, as set forth hereinabove. Referring to the aromatic hydrocarbon subjected to alkylation, it is preferable to have present from 2 to or more, sometimes up to 20, molecular proportions of alkylatable aromatic hydrocarbon per one molecular proportion of the particular reactive olefin-acting compound introduced therewith to the alkylation Zone. The higher molecular ratios of alkylatable aromatic hydrocarbon to olefin are particularly necessary when the olefin employed in the alkylation process is a high molecular weight olefin boiling generally higher than pentenes, since these olefins frequently undergo polymerization prior to or substantially simultaneously with alkylation so that one molecular proportion of such an olefin can thus alkylate two or more molecular proportions of the alkylatable aromatic hydrocarbon. The higher molecular ratios of alkylatable aromatic hydrocarbon to reactive olefin also tend to reduce the formation of polyalkylated products because of the operation of the law of mass action under these conditions.

In converting aromatic hydrocarbons to effect selective alkylation thereof with the type of catalysts herein described, either batch or continuous operations may be employed. The actual operation of the process admits of some modification depending upon the normal phase of the reacting constituents, whether the catalyst utilized is not more than 0.8 gram of boron trifluoride per gram mol of olefin-acting compound along with a boron trifluoride modified sulfur containing alumina, or said boron trifluoride modified sulfur containing alumina alone, and whether batch or continuous operations are employed. In one type of batch operation, an aromatic hydrocarbon to be alkylated, for example, benzene, is brought to a temperature and pressure within the approximate range specified in the presence of a catalyst comprising boron trifluoride and boron trifluoride modified substantially anhydrous sulfur containing-gamma-alumina having a concentration corresponding to a sufliciently high activity and alkylation of the benzene is effected by the gradual introduction under pressure of an ethylene and propylene mixture, in a manner to attain contact of the catalyst and reactants and in a quantity so that the amount of boron trifluoride utilized is up to about 0.8

gram-per gram mol of olefin. After a suifioient time at the desired temperature and pressure, the gases are vented and the selectively alkylated aromatic hydrocarbon separated from the reaction products. The cumene and diisopropyl benzene recovered from the reaction mixture will be separated by conventional means while the vented gas comprising unreacted ethylene may be recovered and stored for further use, or if so desired, may be further utilized in any process where relatively pure ethylene is required.

In another manner of operation, the aromatic hydrocarbon may be mixed with olefins at a suitable temperature in the presence of sufficient boron trifluoride modified sulfur containing alumina, and boron trifluoride is then added to attain an amount between gap up to about 0.8 gram per gam mol of reactive olefin, which in this instance comprises propylene, the ethylene being unreac tive in the presence of the catalyst utilized in the present invention. Reaction is then induced by suificiently long contact time with the catalyst. Alkylation may be allowed to progress to different stages depending upon contact time. In the case of the selective alkylation of benzene with normally gaseous olefins, the most desirable product is that obtained by the utilization in the process of molar quantities of benzene exceeding those of the olefin. In a batch type of operation, the amount of boron trifluoride modified sulfur containing alumina utilized will range from about 1% to about 50% by weight based on the aromatic hydrocarbon. With this quantity of boron trifluoride modified sulfur containing alumina, and boron trifluoride as set forth hereinabove, the contact time may be varied from about 0.1 to about 25 hours or more. Contact time is not only dependent upon the quantity of catalyst utilized but also upon the efficiency of mixing, shorter contact times being attained by increasing mixing. After batch treatment, the boron trifluoride component of the catalyst is removed in any suitable manner, such as by venting or caustic washing, the organic layer or fraction is decanted or filtered from the boron trifluoride modified sulfur containing alumina, and the organic product or fraction is then subjected to separation such as by fractionation for the recovery of the desired reaction product or products.

In one type of continuous operation, a liquid aromatic hydrocarbon, such as benzene, containing dissolved therein the requisite amount of boron trifluoride, may be pumped through a reactor containing a bed of solid boron trifluoride modified sulfur containing alumina. The olefin-acting compound or mixture of olefin-acting compounds may be added to the aromatic hydrocarbon stream prior to contact of this stream with the solid alumina bed, or it may be introduced at various points in the alumina bed, and it may be introduced continuously or intermittently, as set forth above. In this type of operation, the liquid hourly space velocity of the aromatic hydrocarbon reactant will vary from about 0.25 to about 20 or more. The selectively alkylated aromatic compound, which in the case of benzene being subjected to the action of an ethylene-propylene mixture, would comprise cumene and the diisopropy1ben zenes, along with unreacted ethylene is separated and recovered. The details of continuous processes of this general character are familiar to those skilled in the alkylation of aromatic hydrocarbons art and any necessary additions or modifications of the above general procedures will be more or less obvious and can be made without departing from the broad scope of this invention.

The following examples are given to illustrate the proc ess of the present invention which, however, are not intended to limit the generally broad scope of present invention in strict accordance therewith.

EXAMPLE I A catalyst to be used in the present invention was prepared by submerging 200 g. of gamma-alumina in a solution consisting of 450 cc. of benzene and 50 cc. of thiophene for a period of about 64 hours. At the end of this time the benzene-thiophene solution was filtered ofi and the sulfur modified gamma-alumina was recovered and dried. The dried catalyst contained 11.9% thiophene (4.39% sulfur).

The alkylation process was conducted in a once through bench scale processing unit consisting of liquid and gas charge pumps, reaction tube, high pressure controller and liquid and gas collection system. The reactor effluent was collected in the high pressure separator at reactor pressure. Boron trifluoride was metered into the reaction system continuously from a charger under pressure.

The reaction tube was charged with substantially anhydrous sulfur containing gamma-alumina prepared in the above manner from /6" diameter alumina spheres. 30.3 g. of the sulfur containing alumina was charged to the reactor. Prior to contacting of the catalyst with the hydrocarbons the reactor containing the catalyst was slowly pressured to 50 p.s.i.g. with 7 g. of boron trifluoride. A temperature wave increasing from the ambient temperature up to about 58 C. traveled through the alumina bed during the addition of the boron trifluoride. The boron trifluoride was in contact with the alumina for a period of about 1 hour. Then the reaction temperature was increased to 150 C. and the olefin feed was pressured into the reactor to the pump intake pressure. Thereafter both the benzene and the olefin feed pumps were started, the reactor pressure was increased to the 500 p.s.i.g. operating pressure and the input of boron trifluoride was started. The results of this alkylation and the operating conditions utilized are set forth in Table I below.

Table 1 Charge (grams):

Benzene 1871 Cumene .0 Ethylene 40.1 Propylene 54.8

Total 1966 Conditions:

Aromatic/olefin mol ratio 8.54 Liquid hourly space velocity 1.52 Pressure, p.s.i.g 501 Temperature, C., furnace black 149 BF input, gm./ gm. mol olefin 0.1

Recovery, grams, no loss basis:

Ethylene 38.7 Propylene 6.9 Hexene .0 Nonene .0

Benzene 1781.7 Ethylbenzene 5.3 Cumene 103.5 Diethylbenzene .0 Diisopropylbenzene 17.6 Bottoms, 215 C 12.3

Total 1966.0

Grams accounted for, of:

Ethylene 40.1 Propylene 59.1 Benzene 1866.8

Cumene Total 1966.0

Conversion:

Of ethylene, total percent 3.5 Of propylene, total percent 88.3 To cumene, percent 62.6 To diisopropylbenzene, percent 15.4

From the above table it is observed that the alkylation catalyst comprising boron trifluoride and boron trifluoride modified substantially anhydrous sulfur containing alumina selectively alkylated the benzene with propylene forming a high percentage 0 fcumene and diisopropylbenzene as contrasted with the relatively small conversion of ethylene, the major portion of the ethylene being recovered in a state which would allow its use in other chemical processes.

EXAMPLE II A catalyst similar to that set forth in Example I above may be prepared by submerging theta-aluminain a solution of thiophene and benzene. The sulfur containing theta-alumina may be treated with boron trifluoride in a like manner and used as an alkylation catalyst for the alkylation of benzene with an ethylene-propylene feed. The reaction product will consist primarily of cumene and diisopropylbenzene with a relatively small amount of ethylbenzene.

EXAMPLE III In this example a catalyst similar to that set forth in Example I above is prepared by submerging eta-alumina in a solution of thiophene and benzene. The sulfur containing eta-alumina is then treated with boron trifluoride in a like manner and used as an alkylation catalyst for the alkylation of benzene with an ethylene-n-butylene feed. The reaction product will consist primarily of sec-butylbenzene and di-sec-butylbenzene.

We claim as our invention:

1. A process for the production of a selective alkylaromatic hydrocarbon which comprises passing an alkylatable aromatic hydrocarbon, olefin-acting compounds, and not more than 0.8 gram of boron trifluoride per gram mol of olefin-acting compounds to an alkylation zone containing a boron trifluoride modified, sulfur containing alumina, reacting therein said alkylatable aromatic hydrocarbon with said olefin-acting compounds at alkylation conditions in the presence of an alkylation catalyst comprising said boron trifluoride modified, sulfur containing alumina, and recovering therefrom selectively alkylated aromatic hydrocarbon and unreacted olefin-acting compound.

2. A process for the production of a selective alkylaromatic hydrocarbon which comprises passing an alkylatable aromatic hydrocarbon, olefin-acting compounds and not more than 0.8 gram of boron trifluoride per gram mol of olefin-acting compounds to an alkylation zone containing a boron trifluoride modified, substantially anhydrus sulfur containing alumina selected from the group consisting of gamma-alumina, eta-alumina and theta-alumina, reacting therein said alkylat-able aromatic hydrocarbon with said olefin-acting compounds at alkylation conditions in the presence of an alkylation catalyst comprising said boron trifluoride modified, sulfur containing alumina, and recovering therefrom selectively alkylated aromatic hydrocarbon and unreacted olefin acting-compound.

3. A process for the production of a selective alkylaromatic hydrocarbon which comprises passing an alkylat able aromatic hydrocarbon, olefin-acting compounds and not more than 0.8 gram of boron trifluoride per gram mol of olefin-acting compounds to an alkylation zone containing boron trifluoride modified, substantially anhydrous sulfur containing gamma-alumina, reacting therein said alkylatable aromatic hydrocarbon with said olefin-acting compounds at alkylation conditions in the presence of an alky'lation catalyst comprising said boron trifluoride modified, sulfur containing gamma-alumina, and recovering therefrom selectively alkylated aromatic hydrocarbon and unreacted olefin-acting compound.

4. A process for the production of a selective alkylaromlatic hydrocarbon which comprises passing an alkylatable aromatic hydrocarbon, olefin-acting compounds and not more than 0.8 gram of boron trifluoride per gram mol of olefin-acting compounds to an alkylation zone containing boron trifluoride modified, substantially anhydrous sulfur containing theta-alumina, reacting therein said alkylatable aromatic hydrocarbon with said olefin-acting compounds at alkylation conditions in the presence of an alkylation catalyst comprising said boron trifluoride modi fied, sulfur containing theta-alumina, and recovering therefrom selectively alkylated aromatic hydrocarbon and unreacted olefin-acting compound.

5. A process for the production of a selective alkyl-aromatic hydrocarbon which comprises passing an alkylatable aromatic hydrocarbon, unsaturated hydrocarbons and not more than 0.8 gram of boron trifluoride per gram mol of unsaturated hydrocarbons to an alkylation zone contain ing boron trifluoride modified, substantially anhydrous sulfur containing gamma-alumina, reacting therein said alkylatable aromatic hydrocarbon with said unsaturated hydrocarbons at alkylation conditions in the presence of an alkylation catalyst comprising said boron trifluoride modified, sulfur containing gamma-alumina, and recovering therefrom selectively alkylated aromatic hydrocarbon and unreacted unsaturated hydrocarbon.

6. A process for the production of a selective alkylaromatic hydrocarbon which comprises passing an alkylatable aromatic hydrocarbon, unsaturated hydrocarbons and up to about 0.8 gram of boron trifiuoride per gram mol of unsaturated hydrocarbons to an alkylation zone containing boron trifluoride modified, substantially anhydrous sulfur containing gamma-alumina, and reacting therein said alkylatable aromatic hydrocarbon with said unsaturated hydrocarbons at .alkylation conditions in the presence of an alkylation catalyst comprising said boron trifluoride modified substantially anhydrous gamma-alumina, and recovering therefrom selectively alkyated aromatic hydrocarbon and unreaoted unsaturated hydrocarbon.

7. A process for the production of a selective alkylaromatic hydrocarbon which comprises passing an alkylatable aromatic hydrocarbon, unsaturated hydrocarbons and up to about 0.8 gram of boron triflu oride per gram mol of unsaturated hydrocarbons to an alkylation zone containing boron trifluoride modified, substantially anhydrous sulfur containing theta-alumina, and reacting therein said alkylatable aromatic hydrocarbon with said unsaturated hydrocarbons at alkylation conditions in the presence of an alkylation catalyst comprising said boron trifluoride modified, substantially anhydrous theta-alumina, and recovering therefrom selectively alkyated aromatic hydrocarbon and unreacted unsaturated hydrocarbon.

8. A process for the production of a selective alkylaromatic hydrocarbon which comprises passing an alkylatable aromatic hydrocarbon, an olefinic hydrocarbon mixture and up to about 0.8 gram of boron trifluoride per gram mol of reactive olefinic hydrocarbons to an alkylation zone containing boron trifluoride modified, substantially anhydrous sulfur containing gamma-alumina, and reacting therein said alkylatable aromatic hydrocarbon with said olefinic hydrocarbon mixture in the presence of an alkylation catalyst comprising said boron trifiuoride modified, substantially anhydrous gamma-alumina, and recovering therefrom selectively alkylated aromatic hydrocarbon and unreacted olefinic hydrocarbon.

9. A process for the production of a selective alkylaromatic hydrocarbon which comprises passing an alkylatable aromatic hydrocarbon, an olefinic hydrocarbon mixture and up to about 0.8 gram of boron trifluoride per gram mol of reactive olefinic hydrocarbon to an alkylation zone containing boron trifluoride modified, substantially anhydrous sulfur containing theta-alumina, and reacting therein said alkylatable aromatic hydrocarbon with said olefinic hydrocarbon mixture in the presence of an alkylation catalyst comprising said boron trifiuoride modified, substantially anhydrous theta-alumina, and recovering therefrom selectively alkylated aromatic hydrocarbon and unreacted olefinic hydrocarbon.

10. A process for the production of a selective alkylbenzene hydrocarbon which comprises passing an alkylatable benzene hydrocarbon, an olefinic hydrocarbon mixture and up to about 0.8 gram of boron trifiuoride per gram mol of reactive olefinic hydrocarbon to an alkylation zone containing boron trifluoride modified, substantially anhydrous sulfur containing gamma-alumina, reacting therein said alkylatable benzene hydrocarbon with said olefinic hydrocarbon mixture at alkylation conditions in the presence of an alkylation catalyst comprising said boron trifiuoride and boron trifluoride modified, substantially anhydrous sulfur containing gamma-alumina, and recovering therefrom selectively alkylated benzene hydrocarbon and unreacted olefinic hydrocarbon.

11. A process for the production of a selective alkylbenzene hydrocarbon which comprises passing an alkylatable benzene hydrocarbon, an olefinic hydrocarbon mixture and up to about 0.8 gram of boron trifiuoride per gram mol of reactive olefinic hydrocarbon to an alkylation zone containing boron trifluoride modified, substantially anhydrous sulfur containing theta-alumina, reacting therein said alkylatable benzene hydrocarbon with said olefinic hydrocarbon mixture at alkylation conditions in the presence of an alkylation catalyst comprising said boron trifiuoride and boron trifiuoride modified, substantially anhydrous sulfur containing theta-alumina, and recovering therefrom selectively alkylated benzene hydrocarbon andunreacted olefinic hydrocarbon.

12. A process for the production of cumene which comprises passing benzene, an ethylene-propylene mixture and up to about 0.8 gram of boron trifiuoride per gram mol of propylene to an alhylation zone containing boron trifluoride modified, substantially anhydrous sulfur containing gamma-alumina, reacting therein said benzene with said ethylene-propylene mixture at alkylation conditions in the presence of an alkylation catalyst comprising said boron trifiuoride and boron trifiuoride modified, sulfur containing gamma-alumina, and recovering therefrom cumene and unreacted ethylene.

13. A process for the production of cumene which comprises passing benzene, an ethylene-propylene mixture and up to about 0.8 gram of boron trifiuoride per gram mol of propylene to an alkylation zone containing boron trifiuoride modified, substantially anhydrous sulfur containing theta-alumina, reacting therein said benzene with said ethylene-propylene mixture at alkylation conditions in the presence of an alkylation catalyst comprising said boron trifluoride and boron trifiuoride'modified, sulfur containing theta-alumina, and recovering therefrom cumene and unreacted ethylene.

14. A process for the production of cumene which comprises passing benzene, an ethylene-propylene mixture and up to about 0.8 gram of boron trifiuoride per gram mol of propylene to an alkylation zone containing boron trifluoride modified, substantially anhydrous gamma-alurnina containing from about 0.1 to about 10% by weight of sulfur based on the alumina, reacting therein said benzene with said ethylene-propylene mixture at alkylation conditions in the presence of an alkylation catalyst comprising said boron trifluoride and boron trifluoride modified, sulfur containing gamma-alumina, and recovering therefrom cumene and unreacted ethylene.

15. A process for the production of cumene which comprises passing benzene, an ethylene-propylene mixture and up to about 0.8 gram of boron trifiuoride per gram mol of propylene to an alkylation zone containing boron :trifluoride modified, substantially anhydrous theta-alumina containing from about 0.1 to about 10% by weight of sulfur based on the alumina, reacting therein said benzene with said ethylene-propylene mixture at alkylation conditions in the presence of an alkylation catalyst comprising said boron trifiuoride and boron trifiuoride modified, sulfur containing theta-alumina, and recovering therefrom curnene and unreacted ethylene.

16. A process for the production of cumene which comprises passing benzene, an ethylene-propylene mixture and up to about 0.8 gram of boron trifiuoride per gram mol of propylene to an alkylation zone containing boron trifiuoride modified, substantially anhydrous gamma-alumina containing from about 0.1 to about 10% by Weight of sulfur based on the alumina, reacting therein said benzene with said ethylene-propylene mixture at a temperature in the range of from about to about 300 C. and at a pressure in the range of from about atmospheric to about 200 atmospheres in the presence of an alkylation catalyst comprising said boron trifiuoride and boron trifiuoride modified, sulfur containing gammaalumina, and recovering therefrom cumene and unreacted ethylene.

17. A process for the production of cumene which comprises passing benzene, an ethylene-propylene mixture and up to about 0.8 gram of boron trifiuoride per gram mol of propylene to an alkylation zone containing boron trifiuoride modified, substantially anhydrous thetaalumina containing from about 0.1 to about by weight of sulfur based on the alumina, reacting therein said benzene with said ethylene-propylene mixture at a temperature in the range of from about 0 to about 300 C. and at a pressure in the range of from about atmospheric to about 200 atmospheres in the presence of an alkylation catalyst comprising said boron trifiuoride and boron trifiuoride modified, sulfur containing theta-alumina, and recovering therefrom cumene and unreacted ethylene.

18. A process for the production of cumene which comprises passing benzene, an ethylene-propylene mixture and up to about 0.8 gram of boron trifiuoride per gram mol of propylene to an alkylation zone containing boron trifiuoride modified, substantially anhydrous etaalumina containing from about 0.1 to about 10% by weight of sulfur based on the alumina, reacting therein said benzene with said ethylene-propylene mixture at a temperature in the range of from about 0 to about 300 C. and at a pressure in the range of from about atmospheric to about 200 atmospheres in the presence of an alkylation catalyst comprising said boron trifiuoride and boron trifiuoride modified, sulfur containing eta-alumina, and recovering therefrom cumene and unreacted ethylene.

19. A process for the production of sec-butyl-benzene which comprises passing benzene and ethylene-butylene mixture and up to about 0.8 gram of boron trifiuoride per gram mole of propylene to an alkylation zone containing boron trifiuoride modified, substantially anhydrous eta-alumina containing from about 0.1 to about 10% by weight of sulfur based on the alumina, reacting therein said benzene with said ethylene-butylene mix-ture at a temperature in the range of from about 0 to about 300 C. and at a pressure in the range of from about atmospheric to about 200 atmospheres in the presence of an alkylation catalyst comprising said boron trifiuoride and boron trifiuoride modified, sulfur containing etaalumina, and recovering therefrom sec-butylbenzene and unreacted ethylene.

Davis et a1. Mar. 31, 1959 Hervert et al. June 7, 1960 

1. A PROCESS FOR THE PRODUCTION OF A SELECTIVE ALKYLAROMATIC HYDROCARBON WHICH COMPRISES PASSING AN ALKYLATABLE AROMATIC HYDROCARBON, OLEFIN-ACTING COMPOUNDS, AND NOT MORE THAN 0.8 GRAM OF BORON TRIFLUORIDE PER GRAM MOL OF OLEFIN-ACTING COMPOUNDS TO AN ALKYLATION ZONE CONTAINING A BORON TRIFLUORIDE MODIFIED, SULFUR CONTAINING ALUMINA, REACTING THEREIN SAID ALKYLATABLE AROMATIC HYDROCARBON WITH SAID OLEFIN-ACTING COMPOUNDS AT ALKYLATION CONDITIONS IN THE PRESENCE OF AN ALKYLATION CATALYST COMPRISING SAID BORON TRIFLUORIDE MODIFIED, SULFUR CONTAINING ALUMINA, AND RECOVERING THEREFORM SELECTIVELY ALKYLATED AROMATIC HYDROCARBON AND UNREACTED OLEFIN-ACTING COMPOUND. 